1. Technical Field
The present disclosure relates generally to an interleaver and, more particularly, to a bit interleaver that is capable of distributing burst errors occurring in a digital broadcast channel.
2. Description of the Related Art
Bit-Interleaved Coded Modulation (BICM) is bandwidth-efficient transmission technology, and is implemented in such a manner that an error-correction coder, a bit-by-bit interleaver and a high-order modulator are combined with one another.
BICM can provide excellent performance using a simple structure because it uses a low-density parity check (LDPC) coder or a Turbo coder as the error-correction coder. Furthermore, BICM can provide high-level flexibility because it can select modulation order and the length and code rate of an error correction code in various forms. Due to these advantages, BICM has been used in broadcasting standards, such as DVB-T2 and DVB-NGH, and has a strong possibility of being used in other next-generation broadcasting systems.
However, in spite of those advantages, BICM suffers from the rapid degradation of performance unless burst errors occurring in a channel are appropriately distributed via the bit-by-bit interleaver. Accordingly, the bit-by-bit interleaver used in BICM should be designed to be optimized for the modulation order or the length and code rate of the error correction code.